Mapping and geospatial information system (GIS) field workers need to collect positions of assets. A global navigation satellite system (GNSS) such as a global positioning system (GPS) is the tool of choice, but sometimes remote positioning is desired. For example, GPS may not be accurate enough near tall buildings or under trees or overhangs, or the field workers may want to avoid having to physically visit assets in the middle of a road or across a stream.
A simple and efficient workflow is desired where only sub-meter or better accuracy is required (that is, centimeter or millimeter accuracy is not required). Many common scenarios only require a short range of 2-15 meters. For example, if the feature is under a tree or overhang, a good sky-view can usually be obtained only a few meters away. Similarly, a feature may often be inaccessible or inconveniently located, or there may be multiple features within the view of a single location. In each of these instances, it may be difficult or inefficient to physically visit the location of each feature.
Laser rangefinders are commonly used to measure distance. Laser rangefinders are relatively difficult to aim, however, as they often have high-power optical sights. Also, sometimes it is difficult to tell if you are measuring the distance to a target point or the distance to an object that is behind or in front of the target point. Other drawbacks are that the laser rangefinders have to be charged, carried and used, with the attendant bulk, weight, cost, and power consumption.
Other techniques (e.g., bearing-bearing intersection) do not require a laser, but they do require a two-shot workflow. This also requires the operator to move between two different locations to measure a single location and complicates the required calculations. By requiring two locations, the measurements may be difficult to repeat and verify.
Total stations are also sometimes used. While more accurate, the cost, time, and complexity are unattractive.
Thus, there is a general need in the art for a simple, single-shot measurement device and method that is cost effective and convenient for the user.